International Guild of Knot Tyers Forum

General => New Knot Investigations => Topic started by: tsik_lestat on June 13, 2019, 04:38:55 PM

Title: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on June 13, 2019, 04:38:55 PM
Combine a round turn (two turns) and a U turn component, which is formed either from the SPart, or the on-going eye leg, in a nipping structure,(that's the tricky part), and you may end up with a decent bowline.

Consider the first photo, which illustrates such a nipping structure,with just one pass of the Working end.You only have to capture the SE to construct the bight component of the bowline, following then the same path of the returning eye leg and completing the knot.I illustrate the loose knot like this for a clear visual of the nipping structure,which, sometimes, is created by diving with the WE through the right holes/loops.

The second and third photo,show the knot tight in its conventional and detail view accordingly, with the tag end inside the eye of the bowline(it could also be outside).Others might describe such a nipping structure as a crossing knot + nipping turn, unlike the description given earlier.However, the key component here, is the 180 degrees U turn of the on going eye leg (black arrow second picture), which functions as a jam blocker, preventing the collar (near the eye) from blocking. The bight component stabilizes the whole nipping structure in a neat way, creating a stable, jam resistant, TIB knot(if the tag end is tucked back through the collar).

If i was to pinpoint some disadvantages of this knot, i would refer to the bulky form of the TIB version, just for the aesthetics,the non-direct first line of defence,which by the way holds and tightens  very well under load, and the more complex nipping structure.

The ring loading profile is fine for me, but there is always the anti-bowline option, shown in fourth picture(loose), for the rigorous knotting minds.

I think this knot might be a good option for an application where heavy load is expected, being less prone to jamming than a round turn (double) bowline.

Considering the acceptable limit of the two turns around the bight component of a bowline,there are quite a lot (TIB) nipping structures (a bit more complex), that could be stabilized and produce stable,secure,jam resistant bowlines, if anyone feels like investigating in this field.One of the simplest instances of this category of knots is the one presented in this thread,unless someone finds a simpler one and proves me wrong. :)


Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: Dan_Lehman on June 15, 2019, 04:38:50 PM
1) It's NoTIB!  (Do you know what "TIB" means?)
(TIe the ends of a slack line to respective anchors,
then try to tie this knot (or, already tied, to UNtie it).)

2) Your touting it as " less prone to jamming " begs some
evidence that the numerous known bowlines are otherwise!?
In many cases, bowlines can be untied after being loaded
to near rupture forces.  The water (clove h.) bowline and its
similarly built mirrored bowline are *bowlines* that
should be robustly resistant to jamming,
where that possibly is a concern.


--dl*
====
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on June 16, 2019, 05:52:49 PM
With all the respect Dan, i think you might have missed a sentence from my previous initial post!

Quote
creating a stable, jam resistant, TIB knot(if the tag end is tucked back through the collar).

Maybe it is my fault, i should have emphasized the text in brackets.Of course i know what TIB means and i did not illustrated the TIB version of this knot for visual reasons, (for a clear visualization of the nipping structure).I thought that it would be quite obvious for someone to tuck the WE back through the collar and create the TIB version.

I only stated that this knot might be less prone to jamming than a double bowline after being loaded to near rupture forces.I do have a strong preference to jam resistant knots, especially bowlines(the water bowline is no exception,i like it too).

My main goal here, was the incorporation of a U turn component in various nipping structures, which, in some cases, works pretty well and may produce stable, jam resistant bowlines.Nevertheless i have come across with bowlines that do not have the jam resistance property, and i am sure you already knew that.

Thank you for your remarks!
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on June 17, 2019, 04:57:43 PM
Quote
Nevertheless i have come across with bowlines that do not have the jam resistance property

An interesting remark.
As far as I am aware, all 'Bowlines' are jam resistant.
In my view, what you are describing is likely not a 'Bowline'.
A key component of all 'Bowlines' is the nipping loop (which is loaded at both ends, is 'TIB' and has a particular chirality).
It is the nipping loop that plays a pivotal role in the jam resistance.

I'd like to see a clear and unambiguous photo of an alleged 'Bowline' that is vulnerable to jamming.

It is possible that you might be thinking of a 'Bowline' that is built around an #1188 'constrictor hitch' nipping structure.
#1188 is 'TIB' and it is loaded at both ends - so it qualifies as a 'nipping structure'.
However, it does not take the form of a helical loop - so I do not refer to it as a 'nipping loop'.

I struggled for some time in how to conceptualize a 'Bowline' built from #1188 - because I surmised that it might jam.
I am not sure if anyone has load tested such a structure to see if jamming can be induced?
If it turns out that it does jam - then this would be a smoking gun to exclude it from the title of 'Bowline' - and instead 'virtual Bowline'.
In any case, the jury is still out for me on this one...

...

With regard to your use of the descriptor 'Bowline' to describe your creation - I would hesitate to call it 'a' 'Bowline'.
In my view, it is a virtual Bowline.
The nipping structure is TIB and loaded at both ends, but it does not take the form of a helical loop - so this fact ought to disqualify it from being a 'Bowline'.

I use the descriptor virtual Bowline to denote those eye knots that fulfill all the criteria of a Bowline but fall short on account of the geometry of the nipping structure.
All of the primary Bowlines are built from a helical nipping loop that has a defined chirality (either 'S' or 'Z').
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on June 18, 2019, 11:10:27 AM
Thank you Mark, your feedback is all-important and more than welcome as always,especially when it comes to the apply of the theory of bowlines, on various structures and their alleged qualification as bowlines or not.

Now, let's see if i have understood your remarks,since i have some questions that need some sort of clarification.

Quote
I use the descriptor virtual Bowline to denote those eye knots that fulfill all the criteria of a Bowline but fall short on account of the geometry of the nipping structure.

I could accept such a term`virtual bowline`for an eye knot with a nipping structure that deviates from the standard, simple, helical loop, but fullfills all the rest of the criteria, having the jam resistance property at the same time.But i am sure, that you are aware of various eye knots,with nipping structures other than single helical loop, which are vulnerable to jamming, when stabilized as bowlines.Furthermore, if the constrictor bowline that you mentioned in your previous reply, turns out that it does jam (most likely it will), i would hesitate too to add the descriptor `bowline`(even after the adjective virtual) to describe this structure.So, how should we call such knots, virtual bowlines that jam or something else?

To be more specific, the first picture shows an instance of a bowline structure, with a twisted crossing knot nipping component, which i am sure  that you would call it a virtual bowline.To my view, the knot is supersafe, having three direct lines of defence against slippage, but on the other hand, the knot is vulnerable to jamming with this more complex nipping structure (it would be wiser to load the knot in a reverse way, moving the complexity to the collar structure level, and create a less prone to jamming crossing knot based loop). It seems that i have the same problem here, trying to describe and classify this knot.

Quote
As far as I am aware, all 'Bowlines' are jam resistant.
In my view, what you are describing is likely not a 'Bowline'.
A key component of all 'Bowlines' is the nipping loop (which is loaded at both ends, is 'TIB' and has a particular chirality).
It is the nipping loop that plays a pivotal role in the jam resistance.

I'd like to see a clear and unambiguous photo of an alleged 'Bowline' that is vulnerable to jamming.

It is possible that you might be thinking of a 'Bowline' that is built around an #1188 'constrictor hitch' nipping structure

Actually no! I was thinking about a bowline which i have tied recently, and has puzzled me a lot, shown in photos 2,3,4 in a loose conventional and detail view accordingly.It has a simple helical loop nipping component,which is loaded at both ends and it should rather be caregorised as a link TIB bowline (Xarax or Alan Lee probably have tied this).I see a problem in the upper section of the collar structure (near the eye), although the knot has nothing suspicious in it, and i believe that it will block in that point there, or being very difficult to untie after heavy loading!

So how should i call the previous knot, if it has not the jam resistance property?Should i exclude it from the title bowline?

It appears, that the collar structure, plays an important role  to the overall resistance of a bowline knot to jamming, along with the geometry of the nipping structure and the co-operation of those two components.

Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on June 18, 2019, 02:53:00 PM
Quote
It has a simple helical loop nipping component,which is loaded at both ends and it should rather be categorized as a link TIB bowline (Xarax or Alan Lee probably have tied this).

I am not sure why you wish to attach the name 'link bowline' to this structure?
Lees link Bowline is derived from the Lee zep Bowline, which is based on a 'Myrtle'.

Lees link Bowline is (in my view) a marvelous creation. It has no sharp turns - all rope segments turn around at least 2 rope diameters. It also has 3 rope diameters inside the nipping loop.
Your creation has the final reversal tuck going back through the collar - which is a sharp turn around a single rope diameter (which converts it to a TIB knot).

In my view, it is jam resistant - and remain so right up to its MBS yield point.

Quote
if the constrictor bowline that you mentioned in your previous reply, turns out that it does jam (most likely it will), I would hesitate too to add the descriptor `bowline`(even after the adjective virtual) to describe this structure.So, how should we call such knots, virtual bowlines that jam or something else?

Jam resistance is a property inherent to all 'Bowlines' - at least that is the theory.
I did state that I have had difficulties with the so called #1188 Constrictor 'Bowline' - the jury is still out for me.
#1188 constrictor hitch is TIB, loaded at both ends but does not have the geometry of a simple helical loop.
A constrictor is known to jam - and so using it as a nipping structure might violate the principal of jam resistance.

I believe that an eye knot built around a constrictor hitch would qualify as a 'virtual Bowline'.
Using that term removes it from the primary Bowlines family - which all have a helical nipping loop (or double loop per #1013).
So (for me) calling it a Virtual Constrictor Bowline is a safer bet.
And therefore, 'virtual Bowlines' might (in some instances) be vulnerable to jamming.
In contrast, all of the 'primary' Bowlines are jam resistant.

I originally devised the term 'virtual' to describe those eye knots that have nipping structures that are TIB and loaded at both ends - and essentially fulfill all the criteria but for the geometry failing to be a simple helical loop. So for example, an eye knot built around a marlinspike hitch or a crossing hitch (ie Munter hitch) also trigger the use of the descriptor 'virtual Bowline'.

Quote
So how should i call the previous knot, if it has not the jam resistance property?Should i exclude it from the title bowline?
If I have understood you correctly and am viewing the knot images you refer to, then it is jam resistant and it qualifies as a 'Bowline'. If you remove the tail from the collar, it becomes more easy to visualize the 'bight structure' (which consists of the collar and its 2 legs). And indeed, both legs of the collar are fully encircled and clamped by the nipping loop.

Quote
It appears, that the collar structure, plays an important role  to the overall resistance of a bowline knot to jamming, along with the geometry of the nipping structure and the co-operation of those two components.
Xarax has written extensively about the role of the collar in 'Bowlines'.
The collar and its 2 'legs' play an important role in all 'Bowlines'.
In my view, it is the nipping loop that plays a key role in avoiding jamming.
The collar is braced upon the SPart - that is, the SPart acts as a 'bracing post' - which stabilizes the overall bight structure.
To summarize, yes - both the collar (+ both legs) and the nipping loop are the key components of all 'Bowlines'. They are co-dependent.
If there is no nipping loop - this automatically disqualifies an eye knot from being a 'Bowline'.
If there is no collar and/or the 2 legs of the collar are not fully encircled and clamped by the nipping loop, then it is disqualified from being a 'Bowline'.
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: Dan_Lehman on June 18, 2019, 10:13:30 PM
To summarize, yes - both the collar (+ both legs) and the nipping loop are the key components of all 'Bowlines'. They are co-dependent.
If there is no nipping loop, this automatically disqualifies an eye knot from being a 'Bowline'.
If there is no collar and/or the 2 legs of the collar are not fully encircled and clamped by the nipping loop, then it is disqualified from being a 'Bowline'.
This is not MY idea of *bowline*, for the record;
I'm more generous, just wanting the central nipping
loop.  But even then, there come issues with some
of the things such as the water (=>clove h.) bowline
where one can quibble about "nipping loop" as the
outgoing eye leg is now a bit removed from the SPart.

Then come the problematic cases where *loop* seems
to go too far into a *helix*, with increased forces --a change
in identity per loading?  --well, capsizing surely does that!
(And bowlines [#1010[ have capsized, yielding a sort
of noose-hitch w/pile hitch geometry.

<sigh>

--dl*
====
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on June 18, 2019, 11:59:07 PM
I think, i am in a position to say, that i have fully understood your concept of virtual bowlines, due to your in depth analysis in your previous replies, and i see no problem of using that descriptor, for a structure that fulfills all the criteria.

However, in regard to the second knot presented in my previous reply(4), i have a couple of things to clarify ........

Quote
I am not sure why you wish to attach the name 'link bowline' to this structure?

The choice of the name `link`, was not arbitrary. In this particular knot, the link, passes under the SP, collars the on going eye leg, encircling the crossing point of the nipping loop before entering into it. The concept of `link`, has been defined in this forum by Xarax, and i comprehend it as an internal interface, a bridge, between the returning eye leg and the  bight structure of such bowlines, named as link bowlines.

Quote
Lees link Bowline is (in my view) a marvelous creation. It has no sharp turns - all rope segments turn around at least 2 rope diameters. It also has 3 rope diameters inside the nipping loop.

I strongly agree with that statement, and i was not intending to make a comparison.Lee's link bowline, has a different kind of link, (a good one), involving a turn to a certain point of the nipping loop, which retains the jam resistance of the knot.

Quote
If I have understood you correctly and am viewing the knot images you refer to, then it is jam resistant and it qualifies as a 'Bowline'.

Yes, you are refering to the right knot images. My poor evaluation tests, show to me that my link is not so good, it will close too much around the crossing point of the nipping loop, will propably jam, or will be very difficult to untie, while the collar appears to have no such problem.Since i have no scientific evidence to support my claim, i am not putting my arms into fire for this.However, if it turns out that you are right and the knot is jam resistant, when maximally loaded, I have been shooting my own legs regarding this. :) :) :(

To be seen.......................

Thank you for this constructive debate!!!!!

Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on June 19, 2019, 02:38:08 PM
Quote
This is not MY idea of *bowline*, for the record;
I'm more generous, just wanting the central nipping
loop.

As you surely must be aware, Xarax has discussed and debated the role of the Collar with you in substantial detail.
Xarax theories cannot be easily dismissed - as he is usually proven to be correct with the passage of time.

Xarax sees the 'bight component' as a composite structure consisting of a collar and its 2 legs. The 'legs' of the collar must be fully encircled and clamped by the nipping loop.

The nipping loop is the key component of all 'Bowlines' - the absence of which triggers automatic disqualification from the title of 'Bowline'. A nipping loop must be TIB, loaded at both ends and has a defined chirality (either S or Z).

In my view, only requiring a nipping loop is too wide a definition - and has potential to allow many 'ambiguous' eye knots to claim the title of 'Bowline'.

I prefer a more narrow definition - which restricts the number of eye knots that can make a claim to the title of 'Bowline'.
In my view, the collar (and its 2 legs) and the nipping loop are co-dependent and essential components.

Quote
But even then, there come issues with some
of the things such as the water (=>clove h.) bowline
where one can quibble about "nipping loop" as the
outgoing eye leg is now a bit removed from the SPart.

I would posit that a 'Bowline' built around a constrictor hitch is a structure that needs to be assessed - particularly if significant loading can trigger jamming. A constrictor hitch is TIB and loaded at both ends - but, it has a propensity to jam.
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: Dan_Lehman on June 19, 2019, 07:56:15 PM
Quote
This is not MY idea of *bowline*, for the record;
I'm more generous, just wanting the central nipping
loop.

As you surely must be aware, Xarax has discussed and debated the role of the Collar with you in substantial detail.
Xarax theories cannot be easily dismissed - as he is usually proven to be correct with the passage of time.
:o
How on earth does one "prove" a definition to be "correct"?!!
--it is just a way of seeing/grouping things, after all.
If someone excluded what I include (or otherwise has
a different set of things), by what ground is it at all
to be judged for correctness?

(Btw, has time proved his "capstan effect" over your
 pulley'd attempt to test for it?  --or of a sheepshank! ::)  )

Quote
Xarax sees the 'bight component' as a composite structure consisting of a collar and its 2 legs.
What is a "collar" without two legs (or, from the
other side, What are two "legs" absent a collar?!
I.e., the essence of the one implies the other,
so I don't see compositeness to it!

Quote
The 'legs' of the collar must be fully encircled and clamped by the nipping loop.
#1033, is it?, --carrick bwl-- in the returning eye
leg's swinging from turning around the SPart to then
avoid the nipping loop so to turn around an eye leg
begs a question about the above --which can be seen
to come only in an indirect way, and challlenging that
"bight" definition.

Quote
A nipping loop must be TIB, loaded at both ends and has a defined chirality (either S or Z).
Again, these are just from-out-of-the-blue
constraints --and for what point?  One of the
more beautiful *bowlines* has a "cloverhand"
base --though, of course, per that base, NOT
in your set; but firmly in mine.
Note that "TIB" aspect can appear on an extension
to a knot :: so how odd if that then puts in one of
two kin where the other's excluded --but I'm thinking
now of an entire knot and not the component.

Quote
In my view, only requiring a nipping loop is too wide a definition - and has potential to allow many 'ambiguous' eye knots to claim the title of 'Bowline'.
I prefer a more narrow definition - which restricts the number of eye knots that can make a claim to the title of 'Bowline'.
Is this claim such a valuable thing in your mind, in some
kind of *marketing* terms?  --a prize to be closely guarded?!


Quote
Quote
But even then, there come issues with some
of the things such as the water (=>clove h.) bowline
where one can quibble about "nipping loop" as the
outgoing eye leg is now a bit removed from the SPart.

I would posit that a 'Bowline' built around a constrictor hitch is a structure that needs to be assessed - particularly if significant loading can trigger jamming. A constrictor hitch is TIB and loaded at both ends - but, it has a propensity to jam.
But "both ends" are that of the base, which is going
somewhat astray from a "nipping loop".  I was just
able to pull out slack in the middle of the constrictor
and load the knot WITHOUT putting tension through
to this loosened part --challenging the "on both ends"
claim.  And I know that one can do this with the
mirrored bowline (possibly with a purpose to the
pulled-out mid-knot eye!?), rendering it in loading
like mirrored/opposed sheet bends !

You write about the 100%-v-50% difference between
the SPart & outgoing eye leg.  But what is it in the BoaB?!
--by simple-observation math, 100-v-25.  It is then
easy to suggest the climber's old tie-in, bowline on a coil,
and the like Portuguese bwl. as making an even greater imbalance,
and the "tensioned at both ends" claim banks its validity
on little actual tension.
.:. These are problematic things!!

Jamming, as you know, is much material-/load-dependent
(though you have some ideas about calibrating the
load aspect).

In sum, the definition of *bowline* is a choice of how
to speak of things, of what to denote/connote (where
the definition invites/greets newly discovered members).
I find the nipping-loop structure to be a simple aspect
to enable a vast number of ways to use it in making
an eye knot.  You are uncomfortable with the fastness,
and I think want to ascribe also some behavioral aspects
(non-jamming, PETiable?) to it.  One can define things
one way or another, going more general and then having
qualifiers to pick out subsets, or be more particular but
then need ways of combining the narrowly defined things.

I can see myself backing off with "bowline" more to a
stricter "nipping loop"  rule (but I feel no compunction
for "collar") and pushing the more complex bases
(my cloverhand e.g.) into some orbiting set of
associated entities.  Should I do more organizing of
the myriad knots-sketches I have, another way to
group things might come to mind.

My "bowline" vs. "anti-bowline" were already a way
to try to indicate subsets, based on the re-entry of the
returning eye leg --an aspect that at times seemed
unconvincing, where it came in more roundabout
than direct ways (myrtle & my "anti-bwl" being
simple, direct contrasts which give credence to the split).


--dl*
====
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on June 20, 2019, 02:16:55 AM
At this point i would interject and declare that we are now drifting away from Mr tsik_lestat original post.

We are now entering the complex topic of defining what a 'Bowline' is.

But...

Quote
How on earth does one "prove" a definition to be "correct"?!
How does one prove the Earth is spherical (ie not flat)?
How did Einstein prove that gravity isn't a 'force' per se - but, simply the result of curved space (geometry)?

You 'prove' a theory by testing it. If your test finds fault in the theory - you go back to the drawing board and figure out a better theory to explain the findings.

Quote
Btw, has time proved his "capstan effect" over your
 pulley'd attempt to test for it?
I did state that Xarax is usually proven to be correct (usually does not mean 100% of the time).
Even you (Dan) have not been correct 100% of the time.
We all make mistakes or we posit theories which may not be entirely correct.

Xarax devised a clever experiment to 'neutralize' the nipping loop.
Did you see it?
The power of the nipping loop wins over any 'capstan effect'.
The clamping force generated by the nipping loop overshadows any effect of the collar braced upon the SPart.
When the nipping loop is neutralized, we get an opportunity to see the tail segment slip and slide around the SPart (assuming the baseline #1010 Simple Bowline structure).
In devising his experiment, Xarax inadvertently demonstrated the power of the nipping loop.

Quote
What is a "collar" without two legs (or, from the
other side, What are two "legs" absent a collar?!
I.e., the essence of the one implies the other,
so I don't see compositeness to it!

I concur that my use of the word 'composite' was hasty - Xarax did not specifically use that word.
Xarax - as far as I am aware - was the first person to direct attention to the role of the collar, and its 2 'legs'.
I don't recall you (Dan) conceptualizing it in this way?
I intended the word 'composite' to mean 'conglomerate' or 'amalgam' or 'constituent'.
The concept of the 'legs of the collar' assists with identifying if a structure is a 'Bowline' - and yes, #1033 was a useful test vehicle.
The 'legs' of the collar in #1033 have a different geometry compared to the #1010 Simple Bowline.
Ashley appeared to conceptualize 'Bowlines' as having parallel legs of the collar entering through the central nipping loop.
Although Ashley does not appear to specifically use terms such as collar, of legs of the collar - basing his analysis on physical appearance.
In #1033, the legs of the collar enter the nipping loop from opposite directions - but, both legs of the collar are fully encircled and clamped by the nipping loop.
For me, this is one of the key requirements of all 'Bowlines'.
In my view, #1033 is a Bowline - although Ashley did not recognize it as such.
He mistakenly labelled it is a 'carrick' - when in fact if you look closely, it is close but not quite a carrick mat form.
The #1439 derived carrick eye knot is the true carrick 'loop' (not #1033).
But #1439 derived carrick eye knot isn't a 'Bowline' because only one of the legs of the collar is encircled and clamped by the nipping loop.
In #1033, both legs are encircled and clamped by the collar.

I have load tested #1033 and it remains jam resistant right up to its MBS yield point.

per 'TIB' requirement for a nipping loop:
Quote
Again, these are just from-out-of-the-blue
constraints --and for what point?
Nothing out-of-the-blue here at all.
The concept of the 'TIB' requirement for a 'nipping loop' was my attempt to narrow the definition of what a 'nipping loop' is.
I further qualified TIB with the requirement that the 'nipping loop' must be loaded at both ends and will have a defined chirality (either S or Z).

Its about having a set of 'rules' to draw boundaries.
I began with the premise of the simple overhand knot (#514).
I needed a set of rules to distinguish #514 from a nipping loop. And this would enable me to test out the theory.
And this is where I devised the requirement for TIB.
#514 is not TIB - so it is automatically disqualified as being a 'nipping loop'.

In my mind, stipulating a TIB requirement is a simple and elegant way of ruling out a whole cohort of structures which might otherwise be considered as a 'nipping loop'.
But of course this opens the way for #559 Marlinspike hitch and #1195 / #1818 Crossing hitch (Munter hitch).
Eye knots built around #559 or #1818 therefore also must be considered.
And so the 'proper' nipping loop had to take the form of a helical loop - because they both fulfilled the 'chirality' requirement (Munter hitch and Marlinspike hitches both have either S or Z chirality).

But opening up 'Bowlines' to #559 and/or #1818 would also cause difficulties...
And so it seems appropriate to introduce the subset 'Virtual Bowline' - to describe those eye knots which meet all of the requirements for the title of 'Bowline' - but fall just short on account of the geometry of the nipping structure. And here the term 'nipping structure' is used instead of 'nipping loop'.

Quote
You write about the 100%-v-50% difference between
the SPart & outgoing eye leg.  But what is it in the BoaB?!
--by simple-observation math, 100-v-25.

I would caution here that you need to be specific about the loading profile of #1080.
You realize of course that #1080 can be loaded only via  one SPart - where the knot is tied end-of-line - and there is a tail.
In such a case, there is only one (1) functional nipping loop.
The alternative loading profile is where #1080 is tied mid-line and there are now two (2) SParts and two (2) functional nipping loops.

Your math may be affected by loading profile.
Depending on tiny and subtle tying variations, an end-of-line #1080 with only one SPart and one functional nipping loop may have loading bias on just one of the 'eye's. In other words, it is possible that load is biased on just the primary eye (loop) and the secondary eye (loop) has comparatively less load (and if poorly tied - maybe minimal load).

In contrast, if #1080 is tied mid-line and there are two SParts and two functional nipping loops, then you could more confidently state that both the primary and secondary eye share load.
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on June 20, 2019, 05:30:15 PM
Quote
At this point i would interject and declare that we are now drifting away from Mr tsik_lestat original post.

We are now entering the complex topic of defining what a 'Bowline' is.

No worries at all, Mr agent_smith, i don't consider it as a deviation from the norm, or drifting away from my original post. Afterall, when someone uses the word bowline, he should expect such dynamic shifts in the course of the discussion, which i find entirely meaningful and relevant to the initial post, and most of the times equally important, as a presentation of a new structure.

I have been following such constructive debates, since they gave birth to an excellent paper, and they always catch my full attention wherever they take place, under my topic or anywhere else in this forum. I have some difficulties in decoding Dan's writing, but a big cup of coffee helps solving that problem. :) :) 8)

There is always the chance that someone might post a structure,(Alan Lee is a usual suspect), which could negate or expand all the known theory on bowlines, advancing new concepts and triggering similar discussions.
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: Dan_Lehman on June 23, 2019, 08:08:33 PM

Quote
Quote
How on earth does one "prove" a definition to be "correct"?!
...
You 'prove' a theory by testing it.

But it's interesting to wonder how you can conceive this
"*bowline*" as a theory and then would seek to prove that!

--dl*
====
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on June 23, 2019, 10:19:02 PM
Quote
But it's interesting to wonder how you can conceive this
"*bowline*" as a theory and then would seek to prove that!
An example of which is that I theorize that all Bowlines are jam resistant.

tsik_lestat has suggested otherwise but, I need to see evidence of such.

I also theorize that all nipping loops / structures are TIB, jam resistant, have a defined chirality (either S or Z) are loaded at both ends and fully encircle and clamp both legs of the collar.
Be that as it may, the #1249 Constrictor hitch may be troublesome if employed as a nipping structure in a 'Bowline' - and so the theory may have to be modified if it causes jamming.
I don't regard #1249 as a 'loop' - rather, it is a structure. All of the primary Bowlines are built from a helical loop (or double loop per #1013).
I am unclear if anyone has load tested a 'Bowline' built from a #1249 Constrictor to see if jamming can be induced?

Virtual Bowlines built from nipping structures should also be jam resistant.
And so i theorize that if #1249 is used, then the knot ought to be regarded as a 'virtual Bowline' (rather than Bowline).
And if it does jam, then this would mean it fails as a virtual Bowline - because according to (my) theory - all Bowlines - including virtual Bowlines are jam resistant.

Another theory is with regard to effect of having 3 rope diameters inside the nipping loop.
I know that Alan Lee has looked at this but the results have been inconclusive in my view.
A 'control' needs to be used and a statistically valid data set is needed to probe this further.
So its still a 'theory' - until it is proved otherwise.
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on June 25, 2019, 03:52:33 PM
Quote
An example of which is that I theorize that all Bowlines are jam resistant.

tsik_lestat has suggested otherwise but, I need to see evidence of such.

I do not suggest otherwise, i mainly agree with this theorised axiom, i just think that there might be a few structures, that should be considered as special cases, deviating from the jam resistance property.

In the case of nipping structures other than simple helical loop, one should find those with the appropriate geometry, which retains their jam resistance, when stabilized with bight structures, in order to qualify as virtual bowlines.

Quote
the #1249 Constrictor hitch may be troublesome if employed as a nipping structure in a 'Bowline'

True. I was unable to create a jam resistant bowline knot, using a constrictor hitch as nipping structure with the stantard or the Carrick method.Even if the hitch, is to be used as a collar component, in a simple helical nipping loop, for the creation of the "double collar crossed bight bowline", it seems problematic too, in terms of jam resistance.

However, there is a case the hitch might work well, as a collar structure, shown in photos below.First photo shows a bowline with two rope diameter inside the nipping loop.If you want a third one, you move to photos 2,3,4, which show the knot in its loose, conventional and detail view accordingly. If you isolate the collar structure in both TIB knots, it forms the constrictor hitch.

But does the second knot look familiar?Yes it does, it belongs to the End Bound category, as a variation of your EBSB without the Yosemite finish.Probably you have tied it and have dismissed it as inferior?

Judging from your extensive load tests on EBSB, this knot(s) should also be jam resistant!!!!
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: Dan_Lehman on June 25, 2019, 10:31:47 PM
Quote
But it's interesting to wonder how you can conceive this
"*bowline*" as a theory and then would seek to prove that!
An example of which is that I theorize that all Bowlines are jam resistant.
...
:o

You manage to completely miss the point-blank point
--it's about definition!!
(There should be a trophy.)

 :(
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on June 25, 2019, 11:09:43 PM
Quote
You manage to completely miss the point-blank point
--it's about definition!!
(There should be a trophy.)

Obfuscation comes to mind here....
At times, one needs to decode your writing because the underlying intent is oftentimes obscure.
You seek an explanation for how to prove a definition: Which is to seek the meaning of a word, text or concept.

In terms of 'Bowlines' - the title Bowline has a particular meaning to me - but which also has a different meaning to you.
I have attached meaning to how I conceive a nipping loop - of which you conceive is the sole determinant of whether or not an eye knot is to be regarded as a Bowline.

And so a definition, if it is to be applied to a 'Bowline' (for me) requires a set of explicit principles which describes its structure and geometry.
And I derive meaning through understanding.

Beyond that, feel free to seek meaning in your own definitions.
The trophy, if it is to awarded - should go to all who are willing to explore and understand knots and how they work.
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on July 16, 2019, 05:18:06 PM
There is a similar function knot with the initial one, with the only difference that the U turn component, which is formed by the on-going eye leg, exits from the other side, peprendicular to the bight structure of the virtual bowline, acting as an anti-blocking mechanism of the collar which clamps the two legs of the bight component (the extension of SE).

Therefore, when the nipping structure is maximally loaded at both ends, it retains its jam resistance, it is TIB, so the knot qualifies as a  `virtual bowline`.When it comes to ring loading applications, another anti-bowline is available, shown in fourth  image.

Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on July 16, 2019, 11:28:31 PM
Thank you tsik_lestat for another interesting creation.

In my view, you are correct to tot title this creation as a 'virtual Bowline'.
With the term 'virtual' meaning that it is almost, but not quite (and having the appearance of...) fulfilling all of the criteria for 'Bowline'.

The principle reason being the geometry of the nipping loop - which is not a simple helical loop (per #1010) or double helical loop (per #1013).

However, as you correctly point out out - the nipping structure is 'TIB', loaded at both ends, and non-jamming.
There is also a clearly defined collar + 2 legs (which together are holistically a 'bight' component).

And so all the required components are present for title of 'Virtual Bowline'.

Another interesting thought experiment is how Ashley might perceive these types of eye knots - that is, how would he describe them (if he was alive today)?
In my view, all of the 'primary Bowlines' he depicts in his book have a nipping loop based on #1010 or #1013 and there is readily identifiable 'bight structure' which consists of the collar and its 2 leg components. This is where #1033 (Carrick loop) deviated from his concept of a 'bight structure' - and so he did not recognize it as deserving of the title 'Bowline'.
So - in my view, Ashley required both a nipping loop and a bight structure with each of the 'legs' of the bight entering the nipping loop from the same side.
In #1033, the legs of the collar enter the nipping loop from opposite sides. He also appears to 'confuse' #1033 with an eye knot derived from #1439 Carrick bend.
The word 'confuse' is not intended as derogatory or demeaning - as I note that experienced pilots can also get 'confused' and crash the plane. With confusion here taking on a meaning of disorientation, misdirection, distraction, etc. I dont think Ashley had a concept of the correspondence between end-to-end joining knots (ie bends) and 'eye knots' - where each 'bend' appears to have 4 corresponding eye knots. If he had a notional concept of the correspondence of bends such as #1439 with eye knots - he might not have given #1033 the title of 'Carrick loop'.

I note in your creation, that your nipping structure has Z chirality.
This leads me to believe that you are right-handed (is this correct?).
And this is one of the key elements of a nipping loop - that it will have a defined chirality (either S or Z).
Indeed, this is what differentiates a loop from an eye.
An 'eye' has no chirality...but, a loop does have chirality.
For example, the 'eye' of #1047 F8 is not a loop...it has no chirality.

Anyhow, back to your creation...
In its loose dressing state - your nipping structure can be observed as a 'loop' within a 'loop'.
Indeed, one can form a 'loop' (with Z chirality in your case) and then simply induce another twist to form another loop inside the existing loop.
Both 'loops' have Z chirality in your nipping structure.

Quote
with the only difference that the U turn component, which is formed by the on-going eye leg
I believe this statement is technically inaccurate.
By definition, the ongoing (or outgoing) eye leg begins from the point where it exits the 'nipping structure'.
Also, the SPart transitions into the nipping structure at the point where there is an overlap of the SPart and the ongoing/outgoing eye leg.
Indeed, to form a 'loop' - it is created by an overlap of one rope segment riding over/under the other (which gives rise to S or Z chirality).
Your as described 'U turn' is simply existing within the nipping structure - and is a consequence of the 'loop within a loop' geometry.

Practical applications
In some quick and dirty slack shaking, flogging and cyclic loading tests, it seems that your creation is more secure than the #1010 Simple Bowline.
But, it is not inherently secure...but then again, I don't think your intention was to devise an eye knot that could be employed in life critical applications.
In terms of ease of tying, some may struggle...but, I find the easiest method is to form a loop - then induce a twist to form a loop inside a loop and then create the bight structure.
Might be interesting to experiment with a Z/S nipping structure (instead of Z/Z as you depict).
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on July 17, 2019, 03:58:38 PM
Hello agent_smith and thanks for feedback!!

Quote
In my view, you are correct to tot title this creation as a 'virtual Bowline'.
With the term 'virtual' meaning that it is almost, but not quite (and having the appearance of...) fulfilling all of the criteria for 'Bowline'.

Indeed, i had problems to classify various knot structures, but your clever concept of `virtual bowlines`, is more appropriate for nipping structures with geometry that deviates from the simple helical nipping loop, but retains the jam resistance property, serving me well enough, as it extends the scope of the bowline variable, including more structures that would fit in.

Quote
Another interesting thought experiment is how Ashley might perceive these types of eye knots - that is, how would he describe them (if he was alive today)?

I am not sure how Ashley would have categorised these types of eye knots, if he had come across with them.I believe he would have noticed/mentioned some of their good properties, or their potential use in practical applications.

Quote
I note in your creation, that your nipping structure has Z chirality.
This leads me to believe that you are right-handed (is this correct?).

Yes that is correct!! The orientation of my images and the chirality of the nipping component, has revealed my handedness!

Quote
In its loose dressing state - your nipping structure can be observed as a 'loop' within a 'loop'.
Indeed, one can form a 'loop' (with Z chirality in your case) and then simply induce another twist to form another loop inside the existing loop.
Both 'loops' have Z chirality in your nipping structure.

That sounds a bit more complicated than it really is,(reminding me a line from a known movie`a dream within a dream :)).Seriously now, i find your idea of nested loops depicting well enough the geometry of such nipping components. My way of formation of this nipping structure, involves two loops with Z chirality, placing the right over the left one, before stabilizing it with the bight structure. I guess you have already visualized the structure that corresponds to the S chirality, which produces almost the same results, with the difference that the SP and the on going eye leg, exit from the opposite sides. I think it is redundant to post further more images, since it is rather easy to tie the knot with the S chirality, when you have this instance presented here.

Quote
I believe this statement is technically inaccurate.
By definition, the ongoing (or outgoing) eye leg begins from the point where it exits the 'nipping structure'.

Technically, you are absolutely accurate, since the U turn component, is a consequence of the geometry of the nested loops, so i stand corrected.

Quote
In some quick and dirty slack shaking, flogging and cyclic loading tests, it seems that your creation is more secure than the #1010 Simple Bowline.
But, it is not inherently secure...but then again, I don't think your intention was to devise an eye knot that could be employed in life critical applications.

My first priorities when building a knot, are safety and jam resistance. Assuming that we have achieved the second condition, with the easy decompression of the front collar under heavy loading, due to the geometry of the nested loops, in my view, the existence of the two lines of defence against slippage, enhance the safety factor, and if i were to use this knot in a more critical application, i would tuck the WE back through the collar, to add a third level of constriction. But the question still stands!! Would i have to strangle the WE to the SPart? In other words, is this knot inherently secure? You claim that it is not, but i want to know which is the crucial factor that excludes it from being so. I have tied all the inherently secure bowlines depicted in your paper, which are based on a simple nipping component, and a more complex collar structure that secures and buries the tail. But what about the opposite, when it comes to a more complex nipping structure and a simplified collar structure, like the one presented here? I do not wish to add more complexity to the knot with extra tail maneuvers, but i can't help wοndering, if a direct first line of defence would enhance the safety factor, producing an inherently secure knot!!

Quote
Might be interesting to experiment with a Z/S nipping structure (instead of Z/Z as you depict).

That's a brilliant idea and i am already working on it!!! ;)








Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on July 18, 2019, 01:35:27 PM
Quote
Indeed, i had problems to classify various knot structures, but your clever concept of `virtual bowlines`, is more appropriate for nipping structures with geometry that deviates from the simple helical nipping loop, but retains the jam resistance property, serving me well enough, as it extends the scope of the bowline variable, including more structures that would fit in.

I would add that a qualifying requirement is that the nipping structure must also be 'TIB'.
The full suite of qualifying requirements for a nipping structure being:
[ ] TIB
[ ] loaded at both ends
[ ] jam resistant (although this requirement might be problematic with complex structures such as the #1188 Constrictor hitch).

Quote
But the question still stands!! Would i have to strangle the WE to the SPart? In other words, is this knot inherently secure? You claim that it is not, but i want to know which is the crucial factor that excludes it from being so. I have tied all the inherently secure bowlines depicted in your paper, which are based on a simple nipping component, and a more complex collar structure that secures and buries the tail. But what about the opposite, when it comes to a more complex nipping structure and a simplified collar structure, like the one presented here? I do not wish to add more complexity to the knot with extra tail maneuvers, but i can't help wοndering, if a direct first line of defence would enhance the safety factor, producing an inherently secure knot!!

If the bight structure is left in the standard form of #1010 (where the legs of the collar are straight and continue on to form a parallel bight structure) - retardation of tail slippage is reliant only on the nipping structure.
In my view, additional tail maneuvers are required to boost security.
Examples of such tail maneuvers are found in the EBSB Bowline, Lees Link Bowline and Scotts locked Bowline - all of which are inherently secure.

If further tail maneuvers are required to achieve security beyond the base knot form - for example, an additional strangle around the SPart, this implies the base structure is not secure.
For example, Lees link Bowline does not require further tail maneuvers to boost security - it is inherently secure in its native form.

I am of the view that a 'Bowline' with a parallel bight structure in the form of #1010 will (in all likelihood) not be inherently secure.
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: alanleeknots on July 19, 2019, 03:36:42 AM
Quote
There is always the chance that someone might post a structure,(Alan Lee is a usual suspect), which could negate or expand all the known theory on bowlines, advancing new concepts and triggering similar discussions.

Hi All,  Too much time and energy for me to read what you guys wrote, I don't quite understand too.
           But I do look at your  Bowline_with_a_constrictor_ collar_structure_ loose  knot.
           I make a litter change on the tail,  seem like it look nicer this way, see if you like this way or not ?
           謝謝 alanleeknots.
           
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on July 19, 2019, 02:40:46 PM

If further tail maneuvers are required to achieve security beyond the base knot form - for example, an additional strangle around the SPart, this implies the base structure is not secure.

if i wanted to use an additional strangle around the SPart, i would not bother exploring more complex structures, I would use instead a simple standard 1010 bowline (or 1013 double), in TIB fashion, with the WE strangled to lock down the structure.


Examples of such tail maneuvers are found in the EBSB Bowline, Lees Link Bowline and Scotts locked Bowline - all of which are inherently secure.

By the way, i noticed that you have not declared the Ampersand bowline inherently secure!! Are you not satisfied with its locking mechanism which compresses the working end in a neat and effective way, or have you just encountered some vulnerabilities regarding safety?


Hi All,  Too much time and energy for me to read what you guys wrote, I don't quite understand too.
           But I do look at your  Bowline_with_a_constrictor_ collar_structure_ loose  knot.
           I make a litter change on the tail,  seem like it look nicer this way, see if you like this way or not ?
           謝謝 alanleeknots.

They say that an image is equal to thousand words, so you choose to speak through your work with fine quality images and videos of your enormous collection of knots and that's all-important.Thank you for your variation of this knot, looks nice with that slight difference of the tail arrangement, although, i believe it does not alter the overall functionality of the knot. What worries me most, is the constrictor even as a collar structure,which is a known jammer, and i would care for your opinion about if this knot would survive from jamming at maximal loads.

I was hoping to extract a comment from Mr Gommers, because the knot has some resemblance with his EBSB, without the yosemite finish, (also the primary bowline knot, has the WE outside the eye,unlike the EBSB). If it turns out that it does jam, it seems that i have found another bowline knot which is not jam resistant.  :o



Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on August 10, 2019, 02:44:54 PM
Another virtual implementation of a bowline knot, is illustrated in the following images, along with the corresponding anti-bowline in the last picture, which i usually tend to visualize it, as an additional structure.

The nipping structure follows the Z/S chirality this time, as mentioned previously, from left to right accordingly, with two nested loops, where the left (Z), is placed twisted within the right (S), while the returning eye leg, forms the bight structure with the following pattern ~ down, up, down, up, through the two nested loops, from a conventional point of view, as shown in the first or second image, stabilizing the whole structure.

This time, the anti-blocking turn/mechanism,is the extension of the SP, which ensures the jam resistance of the knot, while the on going eye leg, tightens up the front collar and clamps the two legs of the bight component.

The TIB condition also stands in this nipping structure, and the TIB version of the knot is created if the WE is tucked back through the collar of the bowline, plus similar results could be achieved, using an S/Z nipping component.

Perhaps the knot does not win the beauty contest of knots, especially the TIB version, but it certainly does its job very well. :) :)

PS: The collar of the anti-bowline tightens up from the SP this time, while the U anti-blocking turn, is the extension of the on going eye leg (the opposite)
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on August 11, 2019, 01:54:16 AM
Answering a previous post:
Quote
By the way, i noticed that you have not declared the Ampersand bowline inherently secure!! Are you not satisfied with its locking mechanism which compresses the working end in a neat and effective way, or have you just encountered some vulnerabilities regarding safety?
I do not regard the Ampersand Bowline as inherently secure.
It is obviously an improvement over the Simple (#1010) Bowline - but not an improvement to the point where it could be regarded as inherently secure.
And this is in no way intended to be disrespectful to Xarax... I would comment that he didn't specifically intend his Ampersand Bowline to be employed in life critical applications (eg as a tie-in knot for rock climbing). It is a fine creation, but it does not match the inherent security of (for example) Scott's locked Bowline or Lee's link Bowline or my EBSB Bowline.

Quote
The nipping structure follows the Z/S chirality this time, as mentioned previously, from left to right accordingly, with two nested loops, where the left (Z), is placed twisted within the right (S)

To be nit picky, your nipping structure is S/Z (not Z/S).
Also, Z is 'right' and S is 'left'.

...

Otherwise, nice effort - keep up the good work :)

EDIT: Improved attached image quality
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on August 12, 2019, 06:58:25 PM
Thank you agent_smith

Quote
I do not regard the Ampersand Bowline as inherently secure.
It is obviously an improvement over the Simple (#1010) Bowline - but not an improvement to the point where it could be regarded as inherently secure.
And this is in no way intended to be disrespectful to Xarax...

I do not think that a submission of opinion has anything to do with being disrespectful to anyone, if it is supported with valid arguments.Additionally, this very opinion always counts, especially when it comes from an experienced knot tyer and a professional user of knots employed in life critical applications (tie-in knots  for rock climbing).But, to be honest,your answer surprises me a little, i guess i am missing something here, maybe a view from a climber's perspective.

What i do know so far, from the co-creators of Ampersand Bowline, Xarax and Alan Lee, is that the knot has been load-tested extensively to near rupture forces by both of them, and it has been found to be a very secure, stable and jam resistant structure.Perhaps a comment of the original creators would enlighten the situation about the use of this particular knot in life critical applications, of course if they feel appropriate of doing so.

According to my point of view, i have tied the knot countless times and i think that the last tuck of the WE provides more than enough constriction with this squeezing effect from the nipping component with three rope diameters in it, resulting in a very stable supersafe TIB knot.

Furthermore, i have incorporated this technique in bowlines with less stable nipping structures, and found that it works fair well.In some cases , there is the possibility of extra-tucking the Ampersand, gaining further more security, although i believe it is not an essential move.I repeat this is purely my opinion.

Quote
To be nit picky, your nipping structure is S/Z (not Z/S).
Also, Z is 'right' and S is 'left'.

I have attached an image with the initial structure of the previous knot.The left loop (when you face the picture), is a Z loop and the right loop, is an S loop according to your theory, so i call it a Z/S structure.This is the image i was refering to in my previous reply, from left to right (the WE is at the right side when you face the picture). If you consider it from right to left, then it is an S/Z structure. I guess it is a matter of definition. :D








Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on August 13, 2019, 12:04:23 AM
The S/Z was in reference to your bottom image (anti version).
The top image is Z/S. I should have been more clear.

With regard to my statement that the Ampersand Bowline is not inherently secure...I stand by that comment.
For example, I would not use the Ampersand Bowline as a tie-in knot for climbing/mountaineering applications (which are life critical).

The Ampersand Bowline gradually works loose with cyclic / pulsing loading events in some EN892 'half' and 'single' ropes.
Your comment that the knot has been 'load tested' means what exactly?
The default 'pull-it-till-it-yields' type of test reveals nothing.
What matters most is the knots stability and security under cyclic/pulsing loading events, and slack shaking.
s stated, in some types of EN892 ropes - the Ampersand Bowline gradually works loose.
Because of this fact - it does not get over the finish line to be regarded as inherently security.

If you require further proof of this - I suggest you test it yourself with (for example) an Edelrid 'Corbie' 8.6mm EN892 certified climbing rope. Subject the knot to multiple vigorous cyclic / pulsing loading events - in conjunction with slack shaking and observe what happens...

Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on August 16, 2019, 03:46:53 PM
Quote
Your comment that the knot has been 'load tested' means what exactly?
The default 'pull-it-till-it-yields' type of test reveals nothing.

Personally, i do not possess a tensile test rig device to perform the default 'pull it till it yields' type of test, hoping that i shall obtain  and set up one soon enough, because i think it is a very important test for an in depth analysis of a particular knot. And yes, i know/have seen, that pushing a knot to its limits, can reveal many things, such as the response of the knot to linear loading, tail slippage issues, jamming thresolds, how much deformation is induced and if the knot retains its initial shape, how easily it can be untied after rupture occurs e.t.c.

Quote
If you require further proof of this - I suggest you test it yourself with (for example) an Edelrid 'Corbie' 8.6mm EN892 certified climbing rope. Subject the knot to multiple vigorous cyclic / pulsing loading events - in conjunction with slack shaking and observe what happens...

The concept of cyclic/pulsing loading events in conjuction with slack shaking, sounds very important but a little ambiguous to me. I don't have a dynamic rope with these specifications, but if i had, i don't see how i could possibly replicate the failure mode of the Ampersand bowline that you have reported! However, if i ever get one of those, i shall certainly re-ask you about the specific parameters needed to run those cyclic/pulsing loading or slack shaking simulations and not only for the ampersand, but for other knots that i am interested in.

Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on August 16, 2019, 04:51:49 PM
In relation to the typical mindset of pull-it-till-it-yields tests:
Quote
because i think it is a very important test for an in depth analysis of a particular knot
In my experience, the default mindset of pull-it-till-it-yields/breaks actually proves very little.
But if you wish to pursue this standard line of thinking - I would suggest that you would need a specific objective in mind.
Using a control - you could examine the effect of a change in geometry.
For example, you could pull #1010 till it yields say 5 times.
Then, repeat with #1010 Bowline but add 1 extra rope diameter inside the nipping loop (I suggest making it 'slipped' is the easiest method).
Pull it 5 times till it yields.
Compare results.

Quote
The concept of cyclic/pulsing loading events in conjunction with slack shaking, sounds very important but a little ambiguous to me.
How so?

I get the distinct impression that there is some underlying motive here - what is it I wonder?

If you are after a precise ISO definition of how to undertake cyclic load testing of a knot - you will be disappointed.
Same goes for slack shaking and flogging...there is no precise standard that I can point you toward for absolute precision.

Where does that leave you?

It seems that you may find some difficulty in conceptualizing some homebrew style tests of knots.
In my case, I have several different EN892 and EN1891 certified ropes - which presumably gives me a slight advantage in terms of testing with human rated fall-arrest ropes.
When I have tied the Ampersand Bowline (for example) in 8.5mm and 8.6mm EN892 rope, and then subjected it to vigorous slack shaking, I have found that the knot grdually works loose.

How do i define vigorous slack shaking?
Hold the knot in your hand and rapidly shake it about - back n forth, sideways and up and down.

How do i define cyclic loading (of an eye knot)?
Hold the eye in one hand and the SPart in the other - now subject the knot to repetitive pulses of tension followed by slack, followed by tension again (and so on).
Each pulse cycle is just a sudden burst of force using hand strength. You can try 2 to 3 pulses per second by hand...

After doing this for a period of about 1 minute, I find that the Ampersand Bowline begins to loosen.

Interestingly, when i perform the same type of homebrew tests using Scott's locked Bowline - it does not work loose.
What does this mean?

The same can be said of the EBSB Bowline - it does not work loose.

Now, again - would I use the Ampersand Bowline as a tie-in knot for rock climbing?
Answer = No.

...

I'm not sure how much more value I can add to this thread?
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on August 18, 2019, 09:07:36 PM
Thanks for the suggestions in relation to the pull it till it breaks type of test, as well as for the definitions of cyclic loading and slack shaking and for the detailed guidelines of performing these tests. I appreciate all the usefull information that i can get and i tend to absorb it, since i am a newbie to all these. For some time time now, i thought that there was some sort of device generating such cyclic loading oscillations, and it's good to know that such tests can be performed only by hands.

Quote
How so?

I get the distinct impression that there is some underlying motive here - what is it I wonder?

I consider this comment unrelated to knotting!Since when does a query about a test procedure, which i totally ignore, conceal underlying motivation? If you don't approve the word 'ambiguous' replace it with the word 'unknown'. What is obvious to you, may not be for some others!Seek somewhere else for underlying motives, not in my replies, if you feel like doing so.

Quote
Now, again - would I use the Ampersand Bowline as a tie-in knot for rock climbing?
Answer = No.

Yes!I think we have finally got this after three iterations of this statement (or similar) needed in all of your very last three replies!You made your point crystal clear from the very beginning, since i raised my initial question and i do respect your opinion based on your subsequent well-documented replies.Have you sensed some weakness of understanding here and you keep looping this?That's somehow noticeable and worthy of query!

Quote
I'm not sure how much more value I can add to this thread?

Very or none!It depends on the nature of your comments!
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: agent_smith on August 19, 2019, 12:48:20 AM
Quote
I consider this comment unrelated to knotting!Since when does a query about a test procedure, which i totally ignore, conceal underlying motivation? If you don't approve the word 'ambiguous' replace it with the word 'unknown'. What is obvious to you, may not be for some others!Seek somewhere else for underlying motives, not in my replies, if you feel like doing so.
And how is this comment related to knotting science?
You are extrapolating a meaning which is completely far removed from my curiosity.
If you don't approve of the phrase underlying motive , you may replace it with "thought process".

Quote
Yes!I think we have finally got this after three iterations of this statement (or similar) needed in all of your very last three replies!You made your point crystal clear from the very beginning
I'm pleased that you can see my viewpoint - however, is it necessary to overtly re-emphasize it?
Your line of questioning is  probing from several different angles about the security of the Ampersand Bowline - and each time you do this, I simply reply in kind with my viewpoint.

Quote
It depends on the nature of your comments!
With that remark, I will assume that the nature of your comments are made in good faith.
I wish you all the best in your examination of the Ampersand Bowline and other explorations.
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on September 14, 2019, 05:19:50 PM
Last but not least, a helical nipping structure with a U anti-blocking turn, stabilized as a bowline knot, is shown in the following images.The first line of defence has been strengthened, since it is connected directly with the SP, while the front collar (near the eye), which clamps the legs of the bight structure, although it forms a sharp inverse turn, i believe it would survive from maximal loads, due to the other U turn of the nipping structure just before the on-going eye leg.
The result is a stable, secure, jam resistant, virtual bowline, whose TIB version is illustated in the last image.
Title: Re: A round turn + U turn jam resistant TIB bowline(not double)
Post by: tsik_lestat on October 21, 2019, 09:52:38 PM
From the previous nipping structure, if we pass the WE down through the first loop, then we get the Tresse bowline, presented by Alpineer in the following thread,  https://igkt.net/sm/index.php?topic=4321.msg26983#msg26983, another interesting, strong, stabilizing mechanism, whose gripping power might be compared with similar function structures such as the constrictor, but being more prone to jamming at maximal loads.

The nipping structure of another bowline knot, that worths to be mentioned, is shown in the first image, along with the WE passing through it.It can be derived from the previous one, if we follow another path for the SP to avoid the sharp turn of the first one. But does this mat structure look familiar? I did not know its name, but i have located it in the following link, as a Dines arthroscopic knot, analyzed by Xarax as capsized adjustable hitches. https://igkt.net/sm/index.php?topic=4107.msg24631#msg24631.
Capturing the SE with the returning eye leg, can lead to the following attached images of the corresponding bowline, in front, back or TIB fashion accordingly, if the tag end is tucked back through the collar.

In my view, this structure can not jam for two main reasons. Firstly, because of the existence of the U turn component which grips the front collar from one side and holds it, while the helical mechanism of the SP, pushes this very collar down preventing it from closing around itself.

But, this function of this helical SP component, creates a sizeable slack in the collar, which is located to the point where the on-going eye leg exits from the nipping structure and that is a drawback, at least from an aesthetics point of view. Therefore, the knot should be pre-cinched very well, (especially the collar), in the first place.

The Dines knot, illustrated in first image, can be considered as an adjustable mechanism which can capsize to this knot presented also here, https://igkt.net/sm/index.php?topic=6373.0, or a Samisen bowline without the tucking of the tag end.Additionally, it can capsize to the Chinese/loop, a well secured, more of a decorative (or practical) loopknot, which has also been tied by Alan Lee, presented in the following link as cross loopknot. https://www.youtube.com/watch?v=xM-oqzQ4cvs&t

Furthermore, a form of this knot as a bowline is presented here, which features some interesting  knotting aspects.